One typical fuel rail assembly for an internal combustion engine comprises a fuel rail member having a longitudinally extending main fuel passage and several sockets that transversely intersect the main fuel passage at selected locations along its length. An electromechanical fuel injector is disposed in each socket in a sealed manner such that pressurized liquid fuel in the main fuel passage is delivered to the fuel injector without leaking from the fuel rail assembly. When the fuel rail assembly is operatively associated with an engine, the nozzle of each fuel injector is disposed to inject fuel into a corresponding combustion chamber space of the engine in accordance with the selective electrical operation of the fuel injector's solenoid.
The intersection of each socket with the main fuel rail passage creates an opening between them, and at the interior wall surface of the socket this opening is circumscribed by an endless edge. During insertion and removal of a fuel injector into and from a socket, an O-ring seal on the fuel injector passes across this opening. Depending upon the nature of the process for fabricating the fuel rail member, this edge may be sharp, and therefore pose the possibility of damaging the O-ring during the fuel injector's insertion and removal into and from the socket if the O-ring makes contact with the sharp edge. While the exercise of care during the fuel injector's insertion and removal into and from the socket may be sufficient to avoid O-ring damage,.the realities of mass-production assembly and periodic servicing cannot provide 100% assurance that damage will never occur. While it is possible to remove the sharp edge by performing additional secondary operations, e.g., milling, deburring, these measures require additional equipment and processing time, thereby adding to the cost of the fuel rail assembly.
The present invention relates to an innovative solution which is capable of providing improved protection of the O-ring seal during fuel injector installation and removal without incurring the expenses associated with the performance of secondary operations to remove the aforementioned sharp edge. Briefly, the invention comprises the inclusion of two bumpers on the interior wall of the socket, one to either side of the opening between the socket and the main fuel passage, circumferentially about the socket. These bumpers are axially co-extensive with the opening and prevent the O-ring from contacting the edge of the opening. They present smooth rounded surfaces to the fuel injector so that in the event that the O-ring comes into contact with the bumpers during the insertion or removal process, it will pass against a radiused surface that will not damage it. These bumpers can be advantageously incorporated into the fuel rail member by integrally molding them with the socket; in other words, by designing them into the mold that is used to mold the socket so that they are inherently created during the molding process. The illustrated bumpers can be molded without the necessity of undercuts that would require subsequent operations or make the mold more complicated.
Further features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings.